--- layout: default-layout title: class CImageSourceAdapter - Dynamsoft Core Module C++ Edition API Reference description: API reference for the CImageSourceAdapter class in Dynamsoft Core C++ Edition, the abstract base class for all image source adapters that feed images into the capture pipeline. keywords: image source adapter, c++ needAutoGenerateSidebar: true --- # CImageSourceAdapter The `CImageSourceAdapter` class provides an interface for fetching and buffering images. It is an abstract class that needs to be implemented by a concrete class to provide actual functionality. ## Definition *Namespace:* dynamsoft::basic_structures *Assembly:* DynamsoftCore ```cpp class CImageSourceAdapter ``` ## Methods | Method | Description | |--------|-------------| | [`AddImageToBuffer`](#addimagetobuffer) | Adds an image to the buffer of the adapter. | | [`HasNextImageToFetch`](#hasnextimagetofetch) | Determines whether there are more images left to fetch. | | [`StartFetching`](#startfetching) | Starts fetching images. | | [`StopFetching`](#stopfetching) | Stops fetching images. | | [`GetImage`](#getimage) | Returns a buffered image. | | [`SetMaxImageCount`](#setmaximagecount) | Sets how many images are allowed to be buffered. | | [`GetMaxImageCount`](#getmaximagecount) | Returns how many images can be buffered. | | [`SetBufferOverflowProtectionMode`](#setbufferoverflowprotectionmode) | Sets a mode that determines the action to take when there is a new incoming image and the buffer is full. | | [`GetBufferOverflowProtectionMode`](#getbufferoverflowprotectionmode) | Returns the current buffer overflow protection mode. | | [`HasImage`](#hasimage) | Determines whether the image is in the buffer or not. | | [`SetNextImageToReturn`](#setnextimagetoreturn) | Sets the next image to return. | | [`GetImageCount`](#getimagecount) | Returns the actual count of buffered images. | | [`IsBufferEmpty`](#isbufferempty) | Determines whether the buffer is empty. | | [`ClearBuffer`](#clearbuffer) | Clears the image buffer. | | [`SetColourChannelUsageType`](#setcolourchannelusagetype) | Sets the usage type of a color channel in an image. | | [`GetColourChannelUsageType`](#getcolourchannelusagetype) | Gets the usage type of a color channel in an image. | | [`SetErrorListener`](#seterrorlistener) | Sets the error listener for the image source. | ### AddImageToBuffer Adds an image to the buffer of the adapter. ```cpp void AddImageToBuffer(const CImageData* img, bool bClone = true); ``` **Parameters** `[in] img` The image to add to the buffer. `[in] bClone` Whether the image should be cloned before being added to the buffer. **See Also** [CImageData]({{ site.dcvb_cpp_api }}core/basic-structures/image-data.html) ### HasNextImageToFetch Determines whether there are more images left to fetch. ```cpp virtual bool HasNextImageToFetch() const; ``` **Return value** Returns true if there are more images left to fetch, false otherwise. This function must be implemented in the subclass. ### StartFetching Starts fetching images. ```cpp virtual void StartFetching(); ``` ### StopFetching Stops fetching images. ```cpp virtual void StopFetching(); ``` ### GetImage Returns a buffered image. ```cpp virtual CImageData* GetImage(); ``` **Return value** Returns a pointer to the image if it exists in the buffer, NULL otherwise. **See Also** [CImageData]({{ site.dcvb_cpp_api }}core/basic-structures/image-data.html) ### SetMaxImageCount Sets how many images are allowed to be buffered. ```cpp void SetMaxImageCount(int count); ``` **Parameters** `[in] count` The maximum number of images that can be buffered. ### GetMaxImageCount Returns how many images can be buffered. ```cpp int GetMaxImageCount() const; ``` **Return value** Returns the maximum number of images that can be buffered. ### SetBufferOverflowProtectionMode Sets a mode that determines the action to take when there is a new incoming image and the buffer is full. ```cpp void SetBufferOverflowProtectionMode(BufferOverflowProtectionMode mode); ``` **Parameters** `[in] mode` The buffer overflow protection mode to set. **See Also** [BufferOverflowProtectionMode]({{ site.dcvb_cpp_api }}core/enum-buffer-overflow-protection-mode.html?src=cpp&&lang=cpp) ### GetBufferOverflowProtectionMode Returns the current buffer overflow protection mode. ```cpp BufferOverflowProtectionMode GetBufferOverflowProtectionMode() const; ``` **Return value** Returns the current buffer overflow protection mode. **See Also** [BufferOverflowProtectionMode]({{ site.dcvb_cpp_api }}core/enum-buffer-overflow-protection-mode.html?src=cpp&&lang=cpp) ### HasImage Determines whether the image is in the buffer or not. ```cpp bool HasImage(int imageId) const; ``` **Parameters** `[in] imageId` The ID of the image to check. **Return value** Returns true if the image is in the buffer, false otherwise. ### SetNextImageToReturn Sets the next image to return. ```cpp bool SetNextImageToReturn(int imageId, bool keepInBuffer = true); ``` **Parameters** `[in] imageId` The ID of the next image to return. `[in] keepInBuffer` Whether the image should be retained in the buffer, even if the buffer is full and the image needs to be updated based on the `BufferOverflowProtectionMode` parameter. **Return value** Returns true if the image is in the buffer and is set as the next image to return, false otherwise. ### GetImageCount Returns the actual count of buffered images. ```cpp int GetImageCount() const; ``` **Return value** Returns the actual count of buffered images. ### IsBufferEmpty Determines whether the buffer is empty. ```cpp bool IsBufferEmpty() const; ``` **Return value** Returns true if the buffer is empty, false otherwise. ### ClearBuffer Clear the image buffer. ```cpp void ClearBuffer(); ``` ### SetColourChannelUsageType Sets the usage type of a color channel in images. ```cpp void SetColourChannelUsageType(ColourChannelUsageType type); ``` **Parameters** `[in] type` The usage type of a color channel in images to set. **See Also** [ColourChannelUsageType]({{ site.dcvb_cpp_api}}core/enum-colour-channel-usage-type.html?src=cpp&&lang=cpp) ### GetColourChannelUsageType Gets the usage type of a color channel in images. ```cpp ColourChannelUsageType GetColourChannelUsageType() const; ``` **Return value** Returns the usage type of a color channel in images. **See Also** [ColourChannelUsageType]({{ site.dcvb_cpp_api}}core/enum-colour-channel-usage-type.html?src=cpp&&lang=cpp) ### SetErrorListener This function allows you to set an error listener object that will receive notifications when errors occur during image source operations. If an error occurs, the error infomation will be passed to the listener's `OnErrorReceived` method. ```cpp void SetErrorListener(CImageSourceErrorListener* listener); ``` **Parameters** `[in] listener` A pointer to an instance of `CImageSourceErrorListener` or its derived class, which will handle error notifications. **See Also** [CImageSourceErrorListener]({{ site.dcvb_cpp_api }}core/basic-structures/image-source-error-listener.html)